If the stories are true, the Queen watches television drama The Crown without Prince Philip, in what actor Vanessa Kirby describes as loveable and "completely mad".

Kirby portrays the Queen's younger sister Princess Margaret in the lauded true-life telling of the Royal family in the 1940s and '50s, which returns for season two this week.

And she answers the question every fan of the show has asked themselves at some point.

External Link: The Crown season 2 trailer

"Earlier this year we did hear that the Queen watched it and I think [show creator] Peter Morgan was like, 'Don't tell anyone yet because we want to be respectful'," Kirby told News Breakfast.

She said actor Matt Smith — who portrays Prince Philip — had heard the Queen did watch the show, but that the Duke of Edinburgh had not.

"I love that, I love the idea of Philip at home just going, 'I'm not watching that old crap' and the Queen like, 'Come on, darling, come here'."

"The thought of it is completely mad.

"I don't know what they think about how I do Princess Margaret and I would be terrified to hear, I think, in case she's like, 'My sister is nothing like that!'"

'I fell in love with her'

The Crown received a host of awards for its opening season and has a team of researchers on board to try to maintain historical accuracy about the real-life events.

Kirby said she was daunted by taking on the role of Princess Margaret and prepared by listening to her favourite music and hanging pictures of her on the wall in the hope she could "capture the spirit of her as opposed to do an impression".

"She's just got the best spirit ever, such a strong personality, such a force really," Kirby said.

"It was such a gift, I love her. I completely fell in love with her.

Photo: The real Princess Margaret after the announcement of her engagement to Anthony Armstrong Jones. (AP)

"I think she was the best dinner party guest, for all the best reasons: offending everybody, being really nice to some people and then ignoring others.

"I think in the same sentence she could make you feel amazing and really cut you in one go."

External Link: The Crown Instagram post

Season one of the show details Princess Margaret's doomed relationship with Group Captain Peter Townsend and the way the Royal family refused to allow her to marry him.

Season two will focus on her fiery relationship and marriage with photographer Antony Armstrong-Jones — which would ultimately end in divorce in 1978.

Such was the intensity of their early relationship, Armstrong-Jones's biographer Anne de Courcy wrote in a memoir:

"Each was a person of extraordinary sexual magnetism, with a libido to match."

It's a statement that rings true to Kirby.

"That's what is so amazing about Margaret, you would never describe the Queen and Philip like that," she said.

A whole new cast is coming

This will be Kirby's last season on The Crown as the show moves further ahead in time and the actors are replaced with an older cast to play the Royal family.

It's a bittersweet time, Kirby said.

"I cried on the last day, it was pathetic," she said, adding that Claire Foy, who portrays the Queen, was somewhat more subdued.

External Link: The Crown video

"Claire was just knackered, I think [she] was quite numb," she said.

"We always knew it would only ever be two seasons and because of that, I just wanted to make the most of it.

"It's so cool that two other actors get to do it because I never played such a good character that has been so fulfilling and interesting and complicated, so I just feel really happy for them, whoever it is; we don't know yet."